bob kaluza oversaw safety for b.p. aboard the deepwater horizon when the rig exploded. >> i did not cause this tragedy. i am innocent. and i put my trust, reputation, and future in the hands of the judge and the jury. >> reporter: donald vidrine, another b.p. senior supervisor aboard the rig, also pleaded not guilty. they were in charge of a test that indicated a combustible gas had seeped into well. the indictment alleges kaluza and vadrine didn't call engineers on shore to discuss the abnormal readings as required. instead, they allowed work on the well to go on. hours later, volatile gas came up the well and exploded. >> i'm angry that the two middle management guys are going to take the fall. >> reporter: stephen stone, a worker on the deepwater horizon, escaped on a life boat. he's haunted by memories of fellow workers, some injured, shers jumping 60 feet into the gulf. >> i used to be a really happy guy, and now, i'm just angry. just angry all time. >> reporter: shaun clarke, bob kaluza's lawyer, says someone sho